1. Field of the Invention
The present invention relates to a star coupler for local networks of optical communications systems, particularly for optical data bus systems constructed in a star configuration, comprising a passive optical star coupler for distributing one or more optical signals transmitted by subscriber stations and capable of being supplied to the passive optical star coupler via incoming optical waveguides of the network and supplied over outgoing waveguides of the star coupler.
2. Description of the Prior Art
An example of a local network of optical message transmission is an optical data bus constructed in a star configuration. Such data buses, up to the present, are constructed either with a passive optical star coupler or with an active, electrically-operating star coupler, between the incoming and outgoing optical waveguide (cf. M. R. Finley, "Optical Fibers in Local Area Networks--A Review of Current Progress", IFOC Vol. V, 1983, Handbook and Buyers Guide, pp. 47-55). Both variations have considerable advantages and disadvantages in relation to one another. An advantage of the variation utilizing a passive star coupler is that, for N subscribers, a total of only N transmitters is required which are arranged in the subscriber stations. In the configurations utilizing an active star coupler, yet an additional transmitter must be provided at the output side of the star coupler per subscriber. In exchange, with this configuration, the expense for collision recognition and open-wire line configuration drops considerably because the respective installations are necessary only once in a central processing system.